Patent GB-314026-A (GB)
Title: Improvements in or relating to calculating machines
IPC: G06F7/44
Filed: 1929-06-19
Abstract: 314,026. Hofgaard-Remington Corporation, (Assignees of Aktieselskabet Collett & Co.). June 21, 1928, [Convention date]. Drawings to Specification. Adding and subtracting apparatus.-An electric machine having two sets of contact leads corresponding in number to the digits of a numerical system arranged as described in Specification 211,137 is provided with a single set of digit keys, a number of operation control keys, a plurality of registering devices each comprising sets of multiple contact relays with lockable armatures by means of which the current impulses may be registered and stored, and a recording device actuated by the current impulses through the registers for printing the result of the calculating operations. The item set up by depression of the keys (highest order to lowest) is stored in a register by means of locking bars associated with the armatures of the appropriate relays, and means comprising multiple contact reversing switches are provided for transmitting the amount set up in proper denominational order to the locking bars of a second register, which, for adding and subtracting operations, is connected to the first register through a set of multiple contact relays connected in parallel, the transmitting circuits, of each relay being connected up to a different actuating circuit for the locking bar armatures of the second register in such a manner as described in the above mentioned Specification, that the first relay, corresponding to digit value 1, is connected up to actuate the armature representing a value one unit higher while in the next relay the numerical difference will be two, and so on. Subtraction is effected by adding the complement, the transmitting circuits being connected by a switch device, through the operation of a subtraction control key, to the complementary circuits of the multiple relays. Transfer mechanism.-The means for effecting transfer comprises two relay-operated multiple contact switches connected in parallel and arranged in series with the subtraction switch in the transmitting circuit. Printing items and totals.-The items entered in the machine may be recorded by including in the circuit, relays serving to actuate type bars the relays being inserted in the circuit by depression of a control key. Similarly the amounts standing on the registers may be recorded by transmitting the digits registered back to the same register through a circuit in which the actuating relays for the type bars are connected. Multiplying and dividing apparatus. - In the embodiment for carrying out the multiplication process three sets of registering units, a reversing switch device, and a set of multiple contact relays connected through the leads in accordance with the units and tens figures of the partial products of the digits multiplied by themselves are provided. The first factor is entered in the first register by depression of the numeral keys and is then transmitted on depression of a control key through the reversing device to the second register. The second factor is then entered in the first register and the multiplication control key depressed to initiate the multiplication process, the partial products formed by the second factor with the digits of the first factor being transmitted step by step to the third register. In division operations the dividend is entered in the third register by the transmisson thereto of this number set up on the first register whereupon the divisor is entered in the first register. On depression of the division key the digits of the quotient are obtained by a selection process and entered on the second register. If the product of the digit selected say 9, with the two highest denominational digits of the divisor is greater than the corresponding digits of the dividend the transfer relay is energized and causes a division ratchet mechanism to perform a step movement closing a circuit for the next lower digit 8 as a multiplier and so on until a digit is reached which will have no effect on the transfer relay but will initiate the carrying out of the subtraction of the partial product formed from the dividend the process being continued automatically. Various circuits are described for ascertaining the number of digits of an item entered up at a particular moment, for correcting errors by clearing the machine of the number so entered, for optically or otherwise indicating when the capacity of the machine has been exceeded, and for effecting an approximation in the result by discarding one or more decimal places and if necessary correcting the lowest significant digit. Specification 282,582, [Class 38 (v), Electric switches &c.], also is referred to.